I have responses from individuals in the form of a Likert-type scale (range 1-7 where 1=strongly disagree and 7=strongly agree). There are 15 statements in 5 domains (3 statements per domain) relating to vaccine hesitancy, where importantly some statements are negatively worded and some positively worded. Of about 800 responders, about 10 gave the same response to all 15 statements (either strongly disagreed or agreed) and about 70 were always indifferent (all fours). In other words, their responses have no variation at all. Another group of about 20 gave conflicting responses within the same domain. That is, it seems they didn't read the statement carefully, since responses to each statement within the same domain should be correlated.
I'm wondering whether to exclude at least the first group from the analysis because it seems that their responses are irrational, but I don't know whether that's reasonable and if I do, what reference can I cite as justification. I've tried searching for keywords such as transitivity and monotonicity, and while these seem similar, they don't quite fit here.
Any help, including keyword(s) to search for or whether I should just include them all in the analysis, would be highly appreciated. :)